Two-way self-circulation casing treatment device for stability expansion of contra-rotating gas compressor

Abstract

The invention discloses a double-path self-circulation casing treatment device for stability expansion of a contra-rotating gas compressor, and belongs to the technical field of internal flow control of turbomachinery. The device comprises two paths of self-circulation casing treatment devices which are identical in structure and different in axial length, each path is composed of an air suction section, an air injection section and a connecting bridge circuit, the side faces of the two paths of self-circulation casing treatment devices are coplanar to form an integral structure, and the two paths of self-circulation casing treatment devices are evenly distributed outside a contra-rotating compressor casing in the circumferential direction. The two air suction ports are uniformly arranged between the tail edge point of the blade tip of the rear-row rotor and the front edge point of the blade tip of the outlet guide blade, and the axial center points coincide; the axial positions of the two air nozzles are respectively matched with the upstream and downstream 10% axial chord length range of the front edge of the front-row rotor blade tip and the rear-row rotor blade tip; the key structure parameters are matched according to a preset proportion. According to the invention, the front and rear rows of rotor flow fields are accurately covered through double-path independent jet flow, jet flow coupling is avoided, enough pressure difference can still be formed under the low-rotating-speed working condition, stall transposition can be effectively dealt with, and the stability extension stability and adaptability under the variable-rotating-speed-ratio / variable-rotating-speed working condition are improved.

Description

Technical Field

[0001] This invention relates to the field of internal flow control technology for turbomachinery, specifically to a dual-path self-circulating casing treatment device for stabilizing a counter-rotating compressor. Background Technology

[0002] The counter-rotating compressor, a novel axial compressor structure, is characterized by its coaxial, counter-rotating dual-rotor assembly. By having two sets of rotors alternately receive the airflow and perform work, it successfully eliminates the interstage stator blades used for rectification and guidance in traditional axial compressors, achieving significant structural optimization. This design gives it significant comprehensive performance advantages. Not only is the structure more compact, effectively reducing the axial space occupied by the entire unit, but it also significantly reduces the weight of the equipment. Furthermore, its single-stage pressure ratio and thrust-to-weight ratio are superior to traditional structures, demonstrating high application potential and widespread value in power plants with stringent performance and weight requirements, such as advanced aero-turbine engines. Its dual rotors can be independently driven to adjust their speeds, flexibly adapting to the airflow parameter requirements under different operating conditions. This significantly improves the airflow torque transmission efficiency and energy conversion effect. While achieving the same overall pressure ratio, it can significantly reduce the number of compressor stages, further simplifying the overall structure and reducing manufacturing costs.

[0003] While counter-rotating compressors possess numerous performance advantages due to their unique structure that eliminates interstage stator blades, their complex internal flow mechanisms and susceptibility to flow instability phenomena such as rotating stall caused by speed ratio fluctuations, coupled with interference from secondary leakage flow at the blade tips, further compress the stable operating range, becoming a core bottleneck restricting their engineering applications. Casing treatment technology, as a key means of improving compressor flow stability, is widely used to suppress instability. Traditional solutions often employ structures such as circumferential grooves and axial slots, achieving only limited stability enhancement through passive control of the blade tip flow field. Furthermore, these solutions are difficult to adapt to the dynamic flow field characteristics of counter-rotating compressors under varying operating conditions, easily leading to airflow energy loss and failing to balance stability enhancement with aerodynamic efficiency. Self-circulating casing treatment, as a novel active control technology, relies on the flow field self-circulation mechanism to recover and reuse the blade tip leakage flow, making it more suitable for the flow field characteristics of counter-rotating compressors compared to traditional passive solutions. However, current research on this technology is mostly limited to the basic theoretical level. It lacks adaptability to the flow field coupling effect caused by the reverse rotation of the dual rotors in counter-rotating compressors. Existing structural designs struggle to accurately match the dynamic flow field at the blade tips, resulting in problems such as low circulation efficiency and unstable stabilization effects. A mature engineering application solution has yet to be developed. Furthermore, existing self-circulating casing treatment devices mostly employ a single-path design. When the speed ratio of a counter-rotating compressor changes, it easily triggers a special "stall transposition" phenomenon—that is, the stage that first stalls can switch between the front and rear rotors. In this situation, a single-path self-circulating casing treatment device can only regulate the tip leakage flow of one rotor row through jet action, failing to provide effective stabilization protection for the other rotor row and making it difficult to adapt to the flow field requirements after the speed ratio changes.

[0004] Therefore, it is urgent to optimize the structural design of the self-circulating casing treatment device to meet the high-load and wide-condition requirements of the counter-rotating compressor, and to ensure that the self-circulating casing treatment device can improve the stability margin of the counter-rotating compressor at different speed ratios. Summary of the Invention

[0005] The technical problem to be solved: To overcome the shortcomings of existing technologies and further enhance the stability enhancement capability of self-circulating casing treatment devices for rotating compressors, this invention provides a dual-path self-circulating casing treatment device for rotating compressors. It aims to optimize the stability enhancement effect under variable speed ratio and variable speed conditions, so as to solve the problems that existing single-path self-circulating casing treatment devices cannot adapt to the "stall reversal" phenomenon, jet coupling competition, and insufficient pressure difference at low speeds of rotating compressors.

[0006] The technical solution of the present invention is: a dual-path self-circulating casing processing device for counter-rotating compressor stabilization, comprising two self-circulating casing processing devices arranged side by side, the two self-circulating casing processing devices forming an integral structure at the side connection point, and integrally disposed on the radial outer side of the counter-rotating compressor casing. Each self-circulating casing processing unit includes an intake section, an exhaust section, and a connecting bridge. The intake section and the exhaust section are connected by the connecting bridge. The connection between the intake section and the counter-rotating compressor casing is the intake port, and the connection between the exhaust section and the counter-rotating compressor casing is the exhaust port. The two self-circulating casing processing units are completely identical in structure except for the length of their respective connecting bridges. The two intake ports of the two-way self-circulating casing processing device are in the same axial position. The axial center point of each intake port is located downstream of the trailing edge of the rear rotor blade tip, and the axial distance between the intake port and the trailing edge of the rear rotor blade tip is within 0.2-0.4 times the axial chord length of the rear rotor blade tip. The two jet nozzles of the two-way self-circulating casing processing device have different axial positions. The axial center point of the first jet nozzle is located within the range of 10% of the axial chord length of the front rotor blade tip airfoil from upstream to downstream of the leading edge point of the front rotor blade tip. The center point of the second jet nozzle is located within the range of 10% of the axial chord length of the rear rotor blade tip airfoil from upstream to downstream of the leading edge point of the rear rotor blade tip.

[0007] A further technical solution of the present invention is: the two-way self-circulating casing processing device includes a first-way self-circulating casing processing device and a second-way self-circulating casing processing device. The first-way self-circulating casing processing device includes a first intake section, a first exhaust section, and a first connecting bridge. The first intake section corresponds to a first intake port, and the first exhaust section corresponds to a first exhaust port. The second-way self-circulating casing processing device includes a second intake section, a second exhaust section, and a second connecting bridge. The second intake section corresponds to a second intake port, and the second exhaust section corresponds to a second exhaust port. The first and second intake sections have identical structures, the first and second jet sections have identical structures, the first and second intake ports have identical structures, the first and second jet ports have identical structures, and the first and second connecting bridges have identical structures except for their lengths.

[0008] A further technical solution of the present invention is as follows: the inner and outer profiles of the intake section of the two-way self-circulating casing processing device are both arc segments, the inner profile of the intake section is tangent to the inner profile of the connecting bridge, and the outer profile of the intake section is tangent to the outer profile of the connecting bridge; the inner and outer profiles of the jet section are both arc segments, the inner profile of the jet section is tangent to the inner profile of the connecting bridge, and the outer profile of the jet section is tangent to the outer profile of the connecting bridge; the inner and outer profiles of the connecting bridge are both parallel to the profile of the counter-rotating compressor casing.

[0009] A further technical solution of the present invention is: the angle between the inner profile of the intake section of the two-way self-circulating casing processing device and the profile of the counter-rotating compressor casing is 15°~30°; the angle between the outer profile of the intake section and the profile of the counter-rotating compressor casing is greater than or equal to the angle between the inner profile of the intake section and the profile of the counter-rotating compressor casing, and the ratio of the two angles is 1~3.

[0010] A further technical solution of the present invention is: the angle between the inner profile of the jet section of the two-way self-circulating casing processing device and the profile of the counter-rotating compressor casing is 10°~20°, the angle between the outer profile of the jet section and the profile of the counter-rotating compressor casing is greater than or equal to the angle between the inner profile of the jet section and the profile of the counter-rotating compressor casing, and the ratio of the two angles is 1~3.

[0011] A further technical solution of the present invention is that the ratio of the axial length of the intake port of the two-way self-circulating casing processing device to the axial chord length of the rear rotor blade tip is in the range of 0.15 to 0.25.

[0012] A further technical solution of the present invention is that the ratio of the axial length of the jet nozzle to the axial length of the intake nozzle of the two-way self-circulating casing processing device is in the range of 0.25 to 0.5.

[0013] A further technical solution of the present invention is: the inner profile of the connecting bridge of the two-way self-circulating casing processing device is at the same height as the profile of the counter-rotating compressor casing, and the ratio of this height to the axial length of the intake port is 1~2. The inner height of the connecting bridge is the average value of the sum of the axial length of the intake port and the axial length of the exhaust port.

[0014] A further technical solution of the present invention is that the circumferential coverage angle of the integral structure formed by the two-way self-circulating casing processing device is 5°~15°.

[0015] A counter-rotating compressor employing the aforementioned dual-path self-circulating casing processing device is characterized in that, in the counter-rotating compressor, 4 to 8 dual-path self-circulating casing processing devices are evenly distributed circumferentially on the outer wall of the counter-rotating compressor casing.

[0016] The beneficial effects of this invention are: The innovation of the dual-path self-circulating casing treatment device proposed in this invention lies in the dual-path independent and collaboratively integrated self-circulating casing treatment scheme. The two casing treatment devices adopt completely identical structural parameters and are coplanar at their circumferentially adjacent parts to form a whole. By placing the two jet ports in the critical areas of the blade tip flow field of the front and rear rotors respectively, the problem of "stall and reversal" of the front and rear rotors during variable speed operation of the counter-rotating compressor is solved, which leads to the failure of the self-circulating casing treatment stability expansion. This breaks through the limitation of single-path design, which can only control a single row of rotors. In terms of structural parameter optimization, the two intake ports are uniformly set between the trailing edge of the rear rotor blade tip and the leading edge of the outlet guide vane tip. The reasonable range of values ​​for their axial distance from the trailing edge of the rear rotor blade tip, their own axial length, and the angle between the intake section profiles is clearly defined. At the same time, the arrangement interval of the two jet ports is limited, and the ratio of the axial length of the jet port to the intake port and the proportion of the angle between the jet section profiles are standardized, effectively avoiding the coupling competition effect of the two jets. In addition, the inner and outer profiles of the intake and jet sections are all circular arc segments and tangent to the connecting bridge profile. The connecting bridge profile is parallel to the counter-rotating compressor casing profile. The two casing treatment devices are evenly and discretely distributed along the circumference, ensuring smooth flow while taking into account structural compactness.

[0017] The invention offers significant advantages. The dual independent jets can fully cover the flow field at the tips of the front and rear rotor blades. Regardless of changes in the counter-rotating compressor speed ratio or whether stall reversal occurs, it can provide extended stability protection for the rotor that stalls first, greatly improving the stability and adaptability of the device under varying speed ratios and operating conditions. The optimized arrangement and parameter matching of the intake port ensure that a sufficient pressure difference can still be formed between the intake and exhaust ports at low speeds, effectively improving the limited extended stability effect of existing designs at low operating conditions and further expanding the stable operating range of the counter-rotating compressor. Numerical studies conducted on a two-stage counter-rotating compressor (see...) Figure 4 Under various speed ratios and different speed conditions, the dual-path self-circulating casing treatment can effectively improve the stability margin of the counter-rotating compressor. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 Meridional view of a counter-rotating compressor equipped with the dual-path self-circulating casing processing device of the present invention; Figure 2 This is a two-dimensional (in the meridional plane) schematic diagram of one of the self-circulating casing processing devices in the dual-path self-circulating casing processing device of the present invention; Figure 3 A three-dimensional schematic diagram of a counter-rotating compressor with the dual-path self-circulating casing processing device of the present invention (the counter-rotating compressor casing is hidden). Figure 4 The mass flow rate-total pressure ratio characteristic curves of a two-stage counter-rotating compressor before and after the application of the dual-path self-circulating casing treatment of the present invention under different speed matching are shown in the figure (the actual speed of each operating condition is marked in the figure, ORI represents the original solid-wall casing counter-rotating compressor, and SRCT represents the counter-rotating compressor with the dual-path self-circulating casing treatment device).

[0020] In the diagram: 1-Inlet guide vane, 2-Front rotor, 3-Rear rotor, 4-Outlet guide vane, 5-Counter-rotating compressor hub, 6-Counter-rotating compressor casing, 7-First self-circulating casing treatment device, 8-Second self-circulating casing treatment device, 9-Inner profile of the jet section, 10-Inner profile of the connecting bridge, 11-Inner profile of the intake section, 12-Outer profile of the jet section, 13-Outer profile of the connecting bridge, 14-Outer profile of the intake section, 15-Intake section, 151-First intake section, 152-Second intake section, 16-Jet section, 161-First jet section, 162-Second jet section, 17-Connecting bridge, 171-First connecting bridge, 172-Second connecting bridge, 18-Intake port, 19-Jet port. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] An embodiment of the dual-path self-circulating casing processing device for stabilizing a counter-rotating compressor according to the present invention is as follows: Figure 1-3 As shown, this dual-path self-circulating casing processing device is adapted to a counter-rotating compressor that uses an inner and outer coaxial counter-rotating dual-rotor assembly and eliminates interstage stator blades. The counter-rotating compressor includes an inlet guide vane 1, a front rotor 2, a rear rotor 3, an outlet guide vane 4, a counter-rotating compressor hub 5, and a counter-rotating compressor casing 6. The dual-path self-circulating casing processing device is located radially outside the counter-rotating compressor casing and is uniformly and discretely distributed along the circumference of the counter-rotating compressor, with a discrete number of... n = [4, 8], the core of this invention is to achieve efficient control of the flow field at the tips of the front and rear rotor blades through the design of precisely matched structural parameters.

[0023] The dual-path self-circulating casing processing device includes a first-path self-circulating casing processing device 7 and a second-path self-circulating casing processing device 8 arranged side by side. The two self-circulating casing processing devices are coplanar at the connection point on the side (i.e., the axial-radial plane), forming an integral structure. The circumferential coverage angle of this integral structure is... γ , γ = [5°, 15°].

[0024] The first self-circulating casing processing device 7 and the second self-circulating casing processing device 8 are identical in structure except for their axial length. Each self-circulating casing processing device includes an intake section 15, an exhaust section 16, and a connecting bridge 17. The intake section 15 and the exhaust section 16 are connected by the connecting bridge 17. The connection between the intake section 15 and the counter-rotating compressor casing 6 is the intake port 18, and the connection between the exhaust section 16 and the counter-rotating compressor casing 6 is the exhaust port 19. Both the intake port 18 and the exhaust port 19 are connected to the inner cavity of the counter-rotating compressor casing 6.

[0025] Specifically, the first self-circulating compressor casing processing device 7 includes a first intake section 151, a first jet section 161, and a first connecting bridge 171. The first intake section 151 and the first jet section 161 are connected through the first connecting bridge 171. The connection point between the first intake section 151 and the counter-rotating compressor casing 6 is the first intake port, and the connection between the first jet section 161 and the counter-rotating compressor casing 6 is the first jet port. The second self-circulating compressor casing processing device 8 includes a second intake section 152, a second jet section 162, and a second connecting bridge 172. The second intake section 152 and the second jet section 162 are connected through the second connecting bridge 172. The connection point between the second intake section 152 and the counter-rotating compressor casing 6 is the second intake port, and the connection between the second jet section 162 and the counter-rotating compressor casing 6 is the second jet port.

[0026] The first intake section 151 and the second intake section 152 have the same structure, the first jet section 161 and the second jet section 162 have the same structure, the first intake port and the second intake port have the same shape, the first jet port and the second jet port have the same shape, and the first connecting bridge 171 and the second connecting bridge 172 have the same structure except for their length.

[0027] In the dual-circuit casing processing device, both the inner profile 11 and the outer profile 14 of the intake section are arc segments to ensure smooth airflow. The inner profile 11 of the intake section is tangent to the inner profile 10 of the connecting bridge, and the outer profile 14 of the intake section is tangent to the outer profile 13 of the connecting bridge. Both the inner profile 9 and the outer profile 12 of the jet section are arc segments. The inner profile 9 of the jet section is tangent to the inner profile 10 of the connecting bridge, and the outer profile 12 of the jet section is tangent to the outer profile 17 of the connecting bridge. Both the inner profile 10 and the outer profile 13 of the connecting bridge are parallel to the profile of the counter-rotating compressor casing 6 (in this invention, the casing radius of the counter-rotating compressor is a fixed value). The inner and outer profiles of the intake section are tangent to the inner and outer profiles of the connecting bridge, respectively. The inner and outer profiles of the jet section are tangent to the inner and outer profiles of the connecting bridge, respectively, to achieve a smooth transition of the flow channel profile and reduce energy loss during airflow.

[0028] like Figure 2 , Figure 3 As shown, the first intake port of the first self-circulating casing processing device 7 and the second intake port of the second self-circulating casing processing device 8 are axially aligned, uniformly located between the trailing edge of the rear rotor 3 blade and the leading edge of the outlet guide vane 4 blade. That is, the axial center point B1 of the first intake port and the axial center point B2 of the second intake port are at the same axial position. For ease of description, the axial center points of the two intake ports are uniformly referred to as point B. The axial distance between point B and the trailing edge of the rear rotor 3 blade is 0.2-0.4 mm. Ca 2, Ca 2 represents the axial chord length of the blade tip profile of the rear rotor. Preferably, the axial distance between the axial center point B of the intake port and the trailing edge point of the blade tip of the rear rotor is set to 0.32. Ca 2.

[0029] The first jet nozzle of the first-path self-circulating casing processing device 7 and the second jet nozzle of the second-path self-circulating casing processing device 8 have different axial positions. The axial center point of the first jet nozzle is point A1, which is located 10% upstream and downstream of the leading edge of the front rotor 2 blade tip. Ca Within 1 range, Ca 1 represents the axial chord length of the blade tip profile of the front rotor. The axial center point of the second jet nozzle is point A2, which is located 10% upstream and downstream of the leading edge point of the blade tip of the rear rotor (blade 3). Ca Within 2 range, Ca 2 represents the axial chord length of the blade tip profile of the rear rotor. Figure 2 Point A in the diagram only indicates the axial center point of the jet nozzle. When the jet nozzle is the first jet nozzle, the axial center point is point A1; when it is the second jet nozzle, the axial center point is point A2. Preferably, the axial center point A1 of the first jet nozzle is located 5% downstream of the leading edge of the front rotor blade tip. CaAt point 1, the axial center point A2 of the second jet nozzle is set at the leading edge of the rear rotor blade tip to ensure that the two jets accurately cover the leakage flow areas of the front and rear rotor blade tips respectively.

[0030] The two self-circulating casing processing units have the same structure. To facilitate the description of the structure of the two self-circulating casing processing units in the meridional plane, as follows... Figure 2 As shown, taking a two-dimensional view of a self-circulating casing processing device as an example, the specific structural parameter settings of the intake section 15, the exhaust section 16, the connecting bridge 17, the intake port 18, and the exhaust port 19 are introduced.

[0031] Figure 2 In the middle, since the first and second air intake ports have the same shape and position, the axial length of the first air intake port is... l suc1 Axial length of the second intake port l suc2 For ease of description, let the axial length of the intake port 18 be equal to 18. l suc Since the first and second jet nozzles have identical structures, the axial length of the first jet nozzle is... l inj1 Axial length of the second jet nozzle l inj2 For ease of description, let the axial length of the jet nozzle 19 be equal to 1. l inj Since the first intake section 151 and the second intake section 152 have identical structures, the angle between the inner profile of the first intake section 151 and the profile of the counter-rotating compressor casing 6 is... β in1 The angle between the inner profile of the second intake section 152 and the profile of the counter-rotating compressor casing 6 β in2 Equal to the angle between the outer profile of the first intake section 151 and the profile of the counter-rotating compressor casing 6. β out1 The angle between the outer profile of the second intake section 151 and the profile of the counter-rotating compressor casing 6 β out2 For ease of description, let the angle between the inner profile 11 of the intake section and the profile 6 of the counter-rotating compressor casing be denoted as . β in The angle between the outer profile line 14 of the intake section and the profile line 6 of the counter-rotating compressor casing is denoted as . β out Since the first jet section 161 and the second jet section 162 have identical structures, differing only in their axial positions, the angle between the inner profile of the first jet section 161 and the profile of the counter-rotating compressor casing 6 is... α in1 The angle between the inner profile of the second jet section 162 and the profile of the counter-rotating compressor casing 6α in2 Equal, the angle between the outer profile of the first jet section 161 and the profile of the counter-rotating compressor casing 6. α out1 The angle between the outer profile of the second jet section 162 and the type 6 profile of the counter-rotating compressor casing α out2 For ease of description, let's denote the angle between the inner profile line 9 of the jet section and the profile line 6 of the counter-rotating compressor casing. α in The angle between the outer profile line 12 of the jet section and the profile line 6 of the counter-rotating compressor casing is... α out Since the first connecting bridge 171 and the second connecting bridge 172 differ only in axial length, and are otherwise identical in structure and dimensions, the distance from the inner profile of the first connecting bridge 171 to the profile of the counter-rotating compressor casing 6 is... H 1. Distance between the inner profile of the second connecting bridge 172 and the profile of the counter-rotating compressor casing 6. H 2. Same as above, the internal height of the first connecting bridge 171 h 1. Internal height of the second connecting bridge 172 h 2. For ease of description, let the distance from the inner profile 10 of the connecting bridge to the profile 6 of the counter-rotating compressor casing be denoted as . H Let the distance between the inner profile line 10 and the outer profile line 13 of the connecting bridge be the internal height of the connecting bridge 17. h .

[0032] Among them, the angle between the inner profile line 11 of the intake section and the profile line 6 of the counter-rotating compressor casing. β in = [15°, 30°], the angle between the outer profile line 14 of the intake section and the profile line 6 of the counter-rotating compressor casing. β out satisfy β out / β in = [1, 3], axial length of intake port 18 l suc Axial chord length of the rear rotor blade tip profile Ca The ratio of 2 satisfies l suc / Ca 2 = [0.15, 0.25]. The angle between the inner profile 9 of the jet section and the profile 6 of the counter-rotating compressor casing. α in = [10°, 20°], the angle between the jet section profile line 12 and the counter-rotating compressor casing profile line 6. α out satisfy α out / αin = [1, 3], the axial length of the jet nozzle 19 is l inj Axial length of intake port 18 l suc The ratio satisfies l inj / l suc = [0.25, 0.5]. Distance from profile 10 inside the connecting bridge to profile 6 of the counter-rotating compressor casing. H satisfy H / l suc = [1, 2], the internal height of connecting bridge 17 h = ( l inj + l suc ) / 2.

[0033] Preferably, the angle between the inner profile 11 of the intake section and the profile 6 of the counter-rotating compressor casing is... β in Set at 20°, the angle between the outer profile line 14 of the intake section and the profile line 6 of the counter-rotating compressor casing. β out Set at 50°, with an axial length of 18 mm for the intake port. l suc Axial chord length of the rear rotor blade tip profile Ca The ratio of 2 is set to 0.17, and the angle between the inner profile line 9 of the jet section and the profile line 6 of the counter-rotating compressor casing is... α in Set at 15°, the angle between the outer profile line 12 of the jet section and the profile line 6 of the counter-rotating compressor casing. α out The angle is 20°, and the axial length of the jet nozzle 19 is... l inj Axial length of intake port 18 l suc The ratio is set to 0.33, and the distance from the inner profile 10 of the connecting bridge to the profile 6 of the counter-rotating compressor casing is... H Set to 1.33 l suc .

[0034] In this embodiment, the circumferential coverage angle of the dual-path self-circulating casing processing device γ Both are 7.2°. The overall structure of the dual-path self-circulating casing treatment device has 6 units evenly distributed around the circumference of the counter-rotating compressor to ensure the uniformity and consistency of the circumferential flow field control, forming a counter-rotating compressor with a dual-path self-circulating casing treatment device.

[0035] This invention relates to a dual-path self-circulating casing treatment device applied to a counter-rotating axial compressor. Through the coordinated matching of the above parameters, the dual-path self-circulating casing treatment device can effectively avoid the jet coupling competition effect during operation by means of an optimized flow channel structure and a precise jet layout. It can form a sufficient suction-jet pressure difference at low speed conditions, while also dealing with the "stall-reversal" phenomenon. This ensures that the counter-rotating compressor can obtain a stable expansion effect under variable speed ratio and variable speed conditions, while taking into account both aerodynamic efficiency and structural compactness.

[0036] Taking the application of this invention to a two-stage counter-rotating axial flow compressor as an example, the main design parameters of the counter-rotating compressor are shown in Table 1: Table 1 Main design parameters of a certain counter-rotating compressor

[0037] Numerical simulation studies of the self-circulating casing treatment device were conducted on the counter-rotating compressor. The specific implementation process of the numerical calculation is as follows: The counter-rotating compressor and the self-circulating casing treatment were meshed using NUMECA / AUTOGRID5 and NUMECA / IGG modules; the three-dimensional RANS equations were solved using the NUMECA / FINETURBO module, with the SA turbulence model selected. The spatial term was discretized using a second-order central difference scheme, and the time term was solved using the fourth-order Runge-Kutta method; multiple different speed combinations were numerically calculated. The results show that the dual-path self-circulating casing treatment device designed in this invention has good stability enhancement effects under different speed ratios / different speed conditions. Figure 4 The mass flow rate-total pressure ratio characteristic curves of the counter-rotating compressor before and after the dual-path self-circulating casing treatment are given. Table 2 presents the statistics of key stability enhancement parameters in the calculation results, including the stability margin improvement. Defined as:

[0038] in, For the original counter-rotating compressor stall point mass flow rate, Mass flow rate at stall point of the counter-rotating compressor after treatment of the dual-path self-circulating casing. The total pressure ratio at the stall point of the original counter-rotating compressor, The total pressure ratio at the stall point of the counter-rotating compressor after processing by the dual-path self-circulating casing.

[0039] Table 2 and Figure 4 The results show that employing a dual-path self-circulating casing treatment device in a counter-rotating compressor can effectively improve its aerodynamic stability characteristics, significantly widen the compressor's stable operating range, and reduce its stall flow. Furthermore, this casing treatment device exhibits good stability enhancement effects under various speed matching conditions, demonstrating excellent adaptability to variable speed conditions and further improving the compressor's operational stability under off-design conditions.

[0040] Table 2. Improvement in stability margin of a two-stage counter-rotating compressor before and after dual-path self-circulating casing treatment under different speed matching.

[0041] It should be noted that, in this text, the axial direction refers to the direction parallel to the compressor rotor's rotation axis; the circumferential direction refers to the direction of circular motion around the axis within a plane perpendicular to the rotation axis; the radial direction refers to the direction perpendicular to the rotor's rotation axis and pointing outwards along the radius; the leading edge point of the rotor blade tip is the intersection of the leading edges of the suction surface and pressure surface of the corresponding two-dimensional airfoil at the rotor blade tip; the trailing edge point of the rotor blade tip is the intersection of the trailing edges of the suction surface and pressure surface of the corresponding two-dimensional airfoil at the rotor blade tip; and the axial chord length of the front rotor blade tip airfoil... Ca 1 is defined as the axial distance between the leading edge and trailing edge of the front rotor blade tip, and the axial chord length of the rear rotor blade tip airfoil. Ca 2 is defined as the axial distance between the leading edge of the rear rotor blade tip and the trailing edge of the rear rotor blade tip.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-path self-circulating casing processing device for stabilizing a counter-rotating compressor, characterized in that, It includes two self-circulating casing processing units arranged side by side. The two self-circulating casing processing units are coplanar at the side connection point to form an integral structure, and are integrally set on the radial outer side of the counter-rotating compressor casing. Each self-circulating casing processing unit includes an intake section, an exhaust section, and a connecting bridge. The intake section and the exhaust section are connected by the connecting bridge. The connection between the intake section and the counter-rotating compressor casing is the intake port, and the connection between the exhaust section and the counter-rotating compressor casing is the exhaust port. The two self-circulating casing processing units are completely identical in structure except for the length of their respective connecting bridges. The two intake ports of the two-way self-circulating casing processing device are in the same axial position. The axial center point of each intake port is located downstream of the trailing edge of the rear rotor blade tip, and the axial distance between the intake port and the trailing edge of the rear rotor blade tip is within 0.2-0.4 times the axial chord length of the rear rotor blade tip. The two jet nozzles of the two-way self-circulating casing processing device have different axial positions. The axial center point of the first jet nozzle is located within the range of 10% of the axial chord length of the front rotor blade tip airfoil from upstream to downstream of the leading edge point of the front rotor blade tip. The center point of the second jet nozzle is located within the range of 10% of the axial chord length of the rear rotor blade tip airfoil from upstream to downstream of the leading edge point of the rear rotor blade tip.

2. The dual-path self-circulating casing processing device for stabilizing a counter-rotating compressor according to claim 1, characterized in that, The dual-path self-circulating casing processing device includes a first-path self-circulating casing processing device and a second-path self-circulating casing processing device. The first-path self-circulating casing processing device includes a first intake section, a first exhaust section, and a first connecting bridge. The first intake section corresponds to the first intake port, and the first exhaust section corresponds to the first exhaust port. The second-path self-circulating casing processing device includes a second intake section, a second exhaust section, and a second connecting bridge. The second intake section corresponds to the second intake port, and the second exhaust section corresponds to the second exhaust port. The first and second intake sections have identical structures, the first and second jet sections have identical structures, the first and second intake ports have identical structures, the first and second jet ports have identical structures, and the first and second connecting bridges have identical structures except for their lengths.

3. The dual-path self-circulating casing processing device for stabilizing a counter-rotating compressor according to claim 1, characterized in that, The inner and outer profiles of the intake section of the two-way self-circulating compressor casing are both arc segments. The inner profile of the intake section is tangent to the inner profile of the connecting bridge, and the outer profile of the intake section is tangent to the outer profile of the connecting bridge. The inner and outer profiles of the jet section are both arc segments. The inner profile of the jet section is tangent to the inner profile of the connecting bridge, and the outer profile of the jet section is tangent to the outer profile of the connecting bridge. The inner and outer profiles of the connecting bridge are parallel to the profile of the counter-rotating compressor casing.

4. The dual-path self-circulating casing processing device for stabilizing a counter-rotating compressor according to claim 3, characterized in that, The angle between the inner profile of the intake section of the two-way self-circulating casing processing device and the profile of the counter-rotating compressor casing is 15°~30°; the angle between the outer profile of the intake section and the profile of the counter-rotating compressor casing is greater than or equal to the angle between the inner profile of the intake section and the profile of the counter-rotating compressor casing, and the ratio of the two angles is 1~3.

5. The dual-path self-circulating casing processing device for stabilizing a counter-rotating compressor according to claim 3, characterized in that, The angle between the inner profile of the jet section and the profile of the counter-rotating compressor casing of the two-way self-circulating casing processing device is 10°~20°, and the angle between the outer profile of the jet section and the profile of the counter-rotating compressor casing is greater than or equal to the angle between the inner profile of the jet section and the profile of the counter-rotating compressor casing. The ratio of the two angles is 1~3.

6. The dual-path self-circulating casing processing device for stabilizing a counter-rotating compressor according to claim 1, characterized in that, The ratio of the axial length of the intake port of the two-way self-circulating casing processing device to the axial chord length of the rear rotor blade tip profile is in the range of 0.15 to 0.

25.

7. The dual-path self-circulating casing processing device for stabilizing a counter-rotating compressor according to claim 1, characterized in that, The ratio of the axial length of the jet nozzle to the axial length of the intake nozzle of the two-way self-circulating casing processing device is in the range of 0.25 to 0.

5.

8. The dual-path self-circulating casing processing device for stabilizing a counter-rotating compressor according to claim 3, characterized in that, The inner profile of the connecting bridge of the two self-circulating casing processing device is at the same height as the profile of the counter-rotating compressor casing. The ratio of this height to the axial length of the intake port is 1 to 2. The inner height of the connecting bridge is the average of the sum of the axial length of the intake port and the axial length of the exhaust port.

9. The dual-path self-circulating casing processing device for stabilizing a counter-rotating compressor according to claim 1, characterized in that, The circumferential coverage angle of the integrated structure formed by the two-way self-circulating casing processing device is 5°~15°.

10. A counter-rotating compressor employing the dual-path self-circulating casing processing device according to any one of claims 1-9, characterized in that, In this counter-rotating compressor, there are 4 to 8 dual-path self-circulating casing processing devices evenly distributed around the outer wall of the counter-rotating compressor casing.

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